Altitude and wind effects on long jump performance with particular reference to the world record established by Bob Beamon

An analysis of long jump performance, including both the approach and aerial phases, is applied to Bob Beamon's legendary leap at the Mexico City Olympic Games of 1968. It is shown that the combined effects of altitude and wind assistance yielded an increment in the length of the jump of about 31 cm, compared to a corresponding jump at sea level under still air conditions. The main factor is shown to be the increased sprinting speed attained under favourable conditions of wind and altitude.     

贮仓特殊部位的施工

贮仓的漏斗及贮仓群当采用现浇混凝土施工，采用空滑法。应做好支撑杆的加固工作。斗壁施工时比较困难，若采用分开施工法较简单，可连续施工，但必须做好施工缝的接槎工作。     

The impact of electric overhead radiant heating on the indoor environment of historic churches

The impact of electric overhead radiant heaters on the microclimate, air flows, transport and deposition of suspended particulate matter (SPM) was monitored between March 2004 and March 2005 in the historic churches of Saint Michael Archangel in Szalowa and Saint Catherine in Cracow (Poland). The measurements show that although irradiation at the floor level increases temperature and reduces relative humidity in the interior of the church, the effect out of the heated zone and for the surfaces sheltered from irradiation is very limited, i.e. their extent is comparable with natural fluctuations inherent to the local climate of the church. The radiant heaters proved to generate little convectional flow of the air. Therefore, the heating system was not found to increase the concentration of SPM indoors; in particular, no re-suspension of particles already present in the church was observed. This work has demonstrated that the overhead radiant heaters are capable of providing localised heat to the areas where people congregate without adversely affecting painted walls and the works of arts displayed in churches. Care, however, should be taken that sensitive works of art are not exposed to the direct infrared radiation.     

航空体育与飞行员心理品质

飞行员的心理品质是安全飞行的必备条件。首次提出了航空体育在培养飞行员心理品质方面所具有的功效；分析了航空体育与飞行员心理品质之间的内在关系；在讨论现行航空体育教学大纲存在的弊端的基础上，提出了未来航空体育教学中各类项目应有的比例。     

郑州市社区健身场所公共卫生状况的调查与对策

了解郑州市室内外健身场所及健身器械的环境卫生状况,为制定健身场所卫生标准提供科学依据.采用公共场所卫生标准检验方法,对郑州市10家大型健身房开馆时的微小气候(气温、风速和相对湿度)、空气质量(室内CO、CO2浓度和细菌总数)及社区路径健身器械生物性污染现状进行了检测.10家健身房内的CO、CO2浓度和细菌总数随着开馆时间延长而增高,与开馆前相比超标5.8%且差异有统计学意义(P＜0.01);室内、室外健身器械均受到不同程度的生物性污染,其中社区路径健身器械细菌的检出率分别高于室内健身器械.因此,应加强对公共健身场所的卫生管理,制定切实可行的清洁、消毒制度,做好经常性的卫生监督工作.     

Teen Perceptions of the Promotion of Safer Sexual Practices: A Focus Group Study

Teens' own thoughts on fostering safe sexual practice are important perspectives in promoting adolescent sexual health yet are relatively absent in the literature. This focus group study explored teens' perceptions about the supports and challenges that exist as teens strive to engage in healthy sexual practices. Seventy-five teens participated in 11 focus groups using a semi-structured interview guide. School-based health centers provided the setting and facilitated sample recruitment. Focus groups were audiorecorded and transcribed verbatim. Data were analyzed using the focus group guide as a template and typologies, or clusters of concepts, were extracted to establish teen perceptions of the factors that support and challenge their ability to engage in safe sexual practices. The socio-ecological model provided the framework to identify these factors within the individual, family/parent, relational (peer/partner), community, or societal spheres of influence. Results discussed the importance of parents, the value of confidentiality, respect for teen decision-making, relationships skills, developmental aspects of the adolescent years, and social interpretations of gender. These findings revealed important considerations as adults develop policies, messages, and programs designed to promote safe sexual behavior in teens.     

主动进气格栅技术研究

随着主动进气格栅技术在汽车上的逐步使用,主动进气格栅的技术优势逐步体现,文章阐述了主动进气格栅对整车行驶阻力的优化和整车热控制的相关影响,并以线性回归模型的方法对主动进气格栅的标定方法进行了初步探索。     

杭州地区桑树冬芽萌发进程与春季气象条件的关系分析

通过相关分析和通径分析,表明在杭州地区的气候条件下,气温是桑树冬芽萌发的主导因子。日照和降水通过气温而起作用。3月平均气温提高1℃,乌皮桑、荷叶白和一之濑的脱苞期分别提前3 d、5 d和3 d;燕口期分别约提前3 d、4 d和4 d;开叶期分别约提前4 d、5 d和4 d。从脱苞至开叶的天数平均为13 d、10 d和7 d。气温高从脱苞至开叶的天数少,以乌皮桑对气温的反应最敏感。分析结果指出春季稳定通过10℃的始日可作为桑树生长季开始的指标。春季气温呈波状形上升,桑树生长也表现为阶段累积生长。     

高浓度污染气象条件分析和预报

CAPPS预报系统对一、二级空气质量预报效果较好，但高浓度污染预报能力较差．从天气系统和气象条件入手，分析了高浓度污染日的成因，提出将气象条件判别方法、天气学方法和CAPPS等几种预报方法的结果进行集成预报，可以有效地提高高浓度污染预报能力。     

大连市安全农产品的消费者行为及市场拓展研究

安全农产品是改善生态环境、提高农产品质量安全水平的主流产品。初步调查显示,大连的消费者对安全农产品的认知度较高,但也存在着对＂三品＂认识不深入、对＂三品＂市场缺乏信心、＂三品＂价格偏高和销售渠道有限等问题和现象。针对以上问题,文章提出相应的对策和建议。